The invention relates to the field of antennas.
Cylindrical reflector antennas are antennas with a reflector curved in one direction, such as having a parabolic cross section, and flat in the other direction. The reflector has a focal line parallel to the cylindrical axis. An antenna feed may be located along the focal line, centered relative to the reflector. The antenna feed may project electromagnetic radiation towards the reflector, which reflects a beam from the antenna feed and focusses a three-dimensional (3D) radiation beam along the curved direction after it is reflected. The antenna feed may be a dipole antenna located along the focal line. The term antenna feed means the physical antenna components that feed the electromagnetic radiation to the antenna reflector, and/or receive the incoming electromagnetic radiation reflected from the antenna reflector surface. The antenna feeds are generally directed towards the reflector and away from the transmission direction. Cylindrical parabolic antennas may radiate a 3D fan-shaped beam, narrow in the curved direction, and wide in the un-curved or straight direction.
For example, the electromagnetic radiation reaching the cylindrical reflector is reflected towards the feed and focused in a plane perpendicular to the cylindrical axis and is spread out along a plane defined by the cylindrical axis and vertex line. The term vertex line refers to the collection of vertex points of cross sectional parabolas defining the parabolic cylindrical reflector. The term tangent plane is a plane tangent to the parabolas defining the parabolic cylinder reflector and passing through the vertex line. The curved ends of the reflector are sometimes capped by flat plates, to prevent radiation out the ends, and this may be called a pillbox antenna.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the figures.